/*******************************************************************************
 * Copyright (c) 2008 The University of York.
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which is available at https://www.eclipse.org/legal/epl-2.0/
 * 
 * Contributors:
 *     Dimitrios Kolovos - initial API and implementation
 ******************************************************************************/
package org.eclipse.epsilon.common.dt.wizards;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.InvocationTargetException;

import org.eclipse.core.resources.IContainer;
import org.eclipse.core.resources.IFile;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.resources.IWorkspaceRoot;
import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Path;
import org.eclipse.core.runtime.Status;
import org.eclipse.epsilon.common.dt.EpsilonCommonsPlugin;
import org.eclipse.jface.dialogs.MessageDialog;
import org.eclipse.jface.operation.IRunnableWithProgress;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.jface.wizard.Wizard;
import org.eclipse.ui.INewWizard;
import org.eclipse.ui.IWorkbench;
import org.eclipse.ui.IWorkbenchPage;
import org.eclipse.ui.IWorkbenchWizard;
import org.eclipse.ui.PartInitException;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.ide.IDE;

public abstract class AbstractNewFileWizard extends Wizard implements INewWizard {
	protected NewFileWizardPage page;
	private ISelection selection;

	public AbstractNewFileWizard() {
		this(new NewFileWizardPage());
	}
	
	public AbstractNewFileWizard(NewFileWizardPage page) {
		super();
		this.page = page;
		setNeedsProgressMonitor(true);
		setWindowTitle(getTitle());
	}
	
	/**
	 * Adding the page to the wizard.
	 */

	@Override
	public void addPages() {
		page.initialise(selection,getTitle(),getDescription(),getExtension(),getImageDescriptor());
		
		addPage(page);
	}

	/**
	 * This method is called when 'Finish' button is pressed in
	 * the wizard. We will create an operation and run it
	 * using wizard as execution context.
	 */
	@Override
	public boolean performFinish() {
		final String containerName = page.getContainerName();
		final String fileName = page.getFileName();
		IRunnableWithProgress op = monitor -> {
			try {
				doFinish(containerName, fileName, monitor);
			} catch (CoreException e) {
				throw new InvocationTargetException(e);
			} finally {
				monitor.done();
			}
		};
		try {
			getContainer().run(true, false, op);
		} catch (InterruptedException e) {
			return false;
		} catch (InvocationTargetException e) {
			Throwable realException = e.getTargetException();
			MessageDialog.openError(getShell(), "Error", realException.getMessage());
			return false;
		}
		return true;
	}
	
	/**
	 * The worker method. It will find the container, create the
	 * file if missing or just replace its contents, and open
	 * the editor on the newly created file.
	 */

	private void doFinish(
		String containerName,
		String fileName,
		IProgressMonitor monitor)
		throws CoreException {
		// create a sample file
		monitor.beginTask("Creating " + fileName, 2);
		IWorkspaceRoot root = ResourcesPlugin.getWorkspace().getRoot();
		IResource resource = root.findMember(new Path(containerName));
		if (!resource.exists() || !(resource instanceof IContainer)) {
			throwCoreException("Container \"" + containerName + "\" does not exist.");
		}
		IContainer container = (IContainer) resource;
		
		if (fileName.indexOf('.') == -1) {
			fileName = fileName + "." + getExtension();
		}
		
		final IFile file = container.getFile(new Path(fileName));
		try (InputStream stream = openContentStream()) {
			if (file.exists()) {
				file.setContents(stream, true, true, monitor);
			} else {
				file.create(stream, true, monitor);
			}
		} catch (IOException e) {
		}
		monitor.worked(1);
		monitor.setTaskName("Opening file for editing...");
		getShell().getDisplay().asyncExec(() -> {
			IWorkbenchPage page =
				PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage();
			try {
				IDE.openEditor(page, file, true);
			} catch (PartInitException e) {
			}
		});
		monitor.worked(1);
	}
	
	
	/**
	 * We will initialize file contents with a sample text.
	 */

	protected String determineInitialContents() {
		return "";
	}
	
	private InputStream openContentStream() {
		String contents = determineInitialContents();
		return new ByteArrayInputStream(contents.getBytes());
	}

	private void throwCoreException(String message) throws CoreException {
		IStatus status =
			new Status(IStatus.ERROR, "org.eclipse.epsilon.eol.dt", IStatus.OK, message, null);
		throw new CoreException(status);
	}

	/**
	 * We will accept the selection in the workbench to see if
	 * we can initialize from it.
	 * @see IWorkbenchWizard#init(IWorkbench, IStructuredSelection)
	 */
	@Override
	public void init(IWorkbench workbench, IStructuredSelection selection) {
		this.selection = selection;
	}
	
	public abstract String getTitle();
	
	public abstract String getExtension();

	public abstract String getDescription();
	
	public ImageDescriptor getImageDescriptor() {
		return EpsilonCommonsPlugin.getDefault().getImageDescriptor("icons/file.big.gif");
	}
	
}
